Passive immunity is defined as:

• A. The body produces its own antibodies after exposure
• B. Immunity that develops over lifetime
• C. An individual does not produce their own antibodies, but receives them from another source
• D. Passive immunity does not involve antibodies

Answer: (C)

Passive immunity means protection that comes from antibodies that were made by someone else and given to you, rather than your own immune system making them. For example, a newborn receives antibodies from the mother through the placenta or from breast milk, and people can also receive immune sera or monoclonal antibodies after exposure. Because the recipient isn’t producing these antibodies themselves, there’s little or no activation of their own B cells, and no memory is formed, so the protection is immediate but temporary. In contrast, active immunity involves your own body generating antibodies in response to exposure and usually provides longer-lasting protection due to immune memory. The statement that the body produces its own antibodies after exposure describes active immunity, the idea of immunity developing over a lifetime is vague and not specific to passive, and saying passive immunity does not involve antibodies is false.